Automatic furnace



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SNVENTOR L. GARmsoN. AUTOMATIC FUBNACE. APPLICATION FILED MAR. l5. 1.920.. L Paten A. 9, 19231;

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.AUTOMATIC FURN'ACE.

Specification of Letters Patent.

Patented Aug. 9, 1921..

Application med March 15, wao. sanar No. waere.l

To all whom t may concern.'

Be it known that I, LLOYD GARRIsoN, a citizen of the United States, residing at Salt Lake Cit in the county of Salt Lake and State of tah, have invented a new and useful Improvement in Automatic. Furnaces,

ofvwhich the following is a specification. The object of my invention is to provide an automatic furnace which requires a minimum of attention, automatically maintains a desired temperature of air during all conditions of outside temperature, uses cheap grades of vfuel such as slack and pea coal, and reduces the. amount of smoke usually produced by bituminous coal. Its chief application is in residences, but it may be used in larger buildings. It is adapted for use with hot air, hot'water, and steamA furnaces. The apparatus consists essentially of an automatic control actuated both by a thermostat and a time device suchas a clock, a

mechanical Stoker, and the furnace with which they operate.

In the accompanying drawings, Figure 1 is a plan of the automatic control, which' for illustration is nearly the same asthat set forth in my co-pending applications No. 35,147,1iled Nov. 1', 1919. n

Fig. 2 is a side view of the same apparatus.

Figs. 3 and 4 are respectively top-and ri ht elevations of ratchet pulley 10.

igs. 5 and Garerespectively frontand right elevations of the circuit breaker. d kig. 7 is a right elevation of contact Figs. 8 and 9* are Arespectively side and top views of switch drum 9.

Fig. 10 is a plan of the transfer switch 42. Fig. 11 is a plan showing the clock with its electrical contacts.

Fig. 12 is a partial right elevation of Fig. 11.

ig. 13 is a wiring diagram of the complete apparatus.v For simplicity the wirf ing` is not shown in other figures. f

ig. 14 is a side view of the mechanical fuel feed, which for illustration is that shown in my co-pending application No.

335,146, filed Nov. 1, 1919, for gravity feed apparatus.

n Fig. 15 shows the furnace lin partial section and illustrates the method of fuel delivery. 1

Fig.` 16 isan enlargement of the mechanical portion of the fuel feed.

Figs. 17 and 18 are respectively sectional and top views of the chute used to convey p the fuel into the furnace, tion A-'A of Fig. 18.

Fig. 19 is a diagrammatic assembly of'all of the elements of the invention.

The apparatus herein described is essentially the same as that set forth in my ap. plication No. 335,14'8 filed Nov. 1, 1919 for Fig. 17 being secautomatic furnaces, with the addition of the Cable 12 is fastened to pulley 10 by pin 111. l

'Ihe travel of plun er 11 isarestricted by stops 15 and 16 so t at by being pulled the length of its travel within the solenoid, it rotates ratchet pulley 10 one half revolution, or slightly more, in a clockwise direction (Fig. 2). Upon the release of the plunger, spring 13 pulls it back to the position shown, 'at the same time rotating ratchetpulley 10 one half revolution backward. During the forward half revolution of the ratchet pulley the crank is rotated by in 17 which engages shoulder 18, Figs. 3 an 4, but on the reverse half revolution of the pulley, pin 17 travels up incline 19 and falls behind the other shoulder` 18 preparatory to the next half revolution. 'Ihe shaft 6 and crank 7 are prevented from rotating in athe fuel feed as the main draft is closed and opened by the rotation of the crank. Motor 25, Fig. 14, through a speed reducing pulley 26, drives the oscillating slide 27, thus deliveringy fuel from the chute 28 to conveyor 29, which is also driven by motor 25. The travel of slide 27 isy regulated by moving sleeve 30 along arm 31', thus allowing considerable variation in the rate of fuel delivery. Conveyer 29 delivers the fuel to chute 32 through which it runs and falls on the grate 33. If fuel, such as bituminous slack coal, is fed from a chute on to the ordinary flat grate it accumulates in a conical pile in the center of the grate. Under these conditions there is only a small area near the circumference of the grate on which the fuel is sufficiently thin to give proper combustion. When the automatic control starts the feed apparatus it frequently happens with a flat grate that the fire existing in this outer ring of thin fuel is choked or extinguished by the fresh fuel with the result that the temperature at the thermostat continues to fall instead of rising as it would if the fire was active.

the feed. Even when the ire does burn, owing to the small area of useful grate surface included in this outer ring, the ire is so sluggish as to produce very poor regulation and may not attainsuiiicient volume to cause the automatic control to again operate after it has started the feed. Topobviate this condition and produce such a fuel bed as will insure sufficient re to cause the automatic -control to operate and control the furnace at all times I have found it necessary to use a conical or pyramidal grate, or in the case of rectangular fire-boxes, a wedge shaped grate. This issimilar in shape to the pile of -fuel and produces a 4uniform fire over the whole grate surface, with the result that the fire is immediately responsive to the addition of fresh fuel and the increase in temperature necessary to cause the automatic control to close the draft and stop the feed takes place as rapidly as the rate of fuel delivery will permit. The construction of chute 32 is shown more in detail in Fig's.

' 17 and18. I prefer to use a chute covered over the entire length projecting into the furnace as this allows a pre-heating of the air which enters the furnace through this channel and deliversit at the center of the lire. To restrict the amount of air entering the chute, the apron valve` V34 is placed near the upper end of the covered ortion. This is composed of light metal an swings freely on pivots' fastened to or near the top of the chute. Fuel striking the apron lifts it and passes on without perceptible diminution of its speed, but at all other times the apron tends to maintain a vertical position. How- The automatic control, therefore, fails to operate and stop without forced draft. In the event a fan is s used, itis operated by the same motor which drives the fuel feed. In most furnaces, how ever, the natural d-raft is sufficient for good combustion and smoke consumption and I prefer to eliminate the fan because of expense both of first cost and operation.

The time control device is shown in detail in Figs. l0, 11, andl 12. .The clock 35 is shown in outline, Fig. l1. It rests on and is held in place by the metal clips 36. To its minute hand spindle 37 is attached spring 38 which during its hourly rotation touches first the fixed contact 39 and then the movable contact 40. The length of the interval between contact of spring 38 with contacts 39 and 40 is regulated by moving the pointer end of Contact 40 around the graduated dial 41. The electrical connections of the clock to transfer switchk42 is shown in Fig. 13. Current flows from terminal 43 of bell transformer 4 through wire 44, wire 45, clip 36, the frame of the clock, spring 38, and from spring 38 to contact 39 when they touch. From contact 39 the current passes through wire 46, solenoid 47, wire l48 to spring 49, Fig. 10, and thence to the pivoted armature 50, the latter having been tilted to the left previous to the ltouching of spring 38 and contact 39. F rom armature 50 the current flows back to terminal 51 of the transformer by wire 52. The passage of this current through solenoid 47 causes it to attract armature 50, tilting it to the right in the position shown, breaks the contact of springs 49 and 53 with the armature, and makes contact of springs 54 and 55 therewith. Breaking of contact between spring 49 and the armature, of course, breaks the circuit through solenoid 47. 4When spring 38 touches contact 40 current flows as before from transformer 4 to spring 38, thence to contact 40, through wire 56, solenoid 57, wire 58, spring 54, izo-,armature 50 and back to the transformer as before. The energizing of solenoid 57 attracts armature 50, tilts it to the left, breaks contact of springs 54 and 55 therewith, and remakes the contact of springs 49 and 53. Armature 50 thus oscillates rst to the right and then to the left as contact is -made by sprin`38 with contacts 39 and 40 respectively. shown later.

The operation of the apparatus as a whole is best shown by Fig. 13. In the diagram, spring 38 is shown as just having touched contact 39 thus tilting armature 50 to the hek object of this will be right, contact therewith of spring 53 being y broken and spring 55 made. Assuming the ,main draft 23 to have been closed previously neeaeee to this action, and the crank 7 pointing in a downward direction, current Hows from terminal 43 of transformer 4 throu h wire '44, solenoids 3, wire 59, terminal 60 igs. 5 and 6), lever arm 6.1, spring 62, to the metal base 1 thence to contact disk 8, spring 2O (Fig. 73, wire 63, wire 64, spring 55, armature 50, wire 52, to terminal 51 of the transformer. The passage of this current through solenoids 3 attracts armature 65 (Fig. l.) and by rotating lever arm 66 closes switch 67. burrent then flows from main 68 through switch 67, solenoid 2, fuse 69, to main 70. The energizing of solenoid 2 attracts plunger 11 and rotates crank 7 and shaft 6 one alf revolution, thus opening draft 23, closing draft 24, and closing the circuit through motor 25 at switch drum 9. At'the same' time contact disk 8 by its half revolution brings insulation 22 in contact with spring 20 thus breaking the existing circuit through solenoids 3 and allowing spring 21 to come In contact with the metal of disk 8. The circuit through solenoids 3 is also broken when pin 71 (Flgs. 3 and 4) strikes lever arm 61 and breaks its contact with spring 62. The breaking of the circuit through solenoids 3 releases lever arm 66, the circuit through solenoid 2 is broken at switch 67 and lunger 11 returns to the position shown as eretofore described. 0n the reverse half revolution of ratchet pulley 10, pin 72 strikes lever arm 61 and remakes its contact with spring 62.

The thermostat 73 has no function in the action just described. The clock by causing the action insures thatv a certain amount of fuel will feed into the furnace each hour irrespective of the temperature requirements, and this amount is regulated by the position of the movable contact 40. Such a provision is necessary to prevent the extinction of the fire during the warmer-months.

After the operation just described the temperature begins to rise. When spring '38 touches contact 40, armature 50 is tilted to the left, making contact with sprin 53. As soon as the ltemperature reaches the upper limit for which the thermostat 73 is set, leaf 74 touches terminal7 5. Current then flows .through solenoids 3 as before except thatit leaves contact disk 8 at sprin 21, traverses wire'76, leaf 74, wire 77, an spring 53 to armature 50. The passage of this current through solenoids 3 causes solenoid 2 to again operate and rotate the shaft another half revolution, closing draft 23, o ening draft 24, and stopping motor 25. f the temperature falls to thelower limit before spring 38 again touches contact 39, leaf 74 touches terminal 78 ofthe thermostat, a ain closing the circuit through solenoids 3. his circuit is the same as that last described eX- cept that the current leaves disk 8 by spring 20, and passes to leaf 74 by wires 63 and 64.

Terminals 75 and 78 of the thermostat re adjustable to allow a temperature variation.

The furnace is therefore always operating from the timespring 38 touches contact 39 until it touches contact 40; during the remainder of the hour it is under control of the thermostat.

The function of springs 79 and 80 (Figs, 1 and 13) is that of a sho-rt .circuiting device for the thermostat. As lever arm 66 rotates, springs 79 and 80 touch, preferably before the closing of switch 67. The thermostat is' then short circuited and the actuating current passes from spring 62 through base 1, spring 80, spring 79, wire 81, to wire 52. ThisY circuit is broken when pin 71 strikes-lever arm 6l. The function of the insulation 22 on the periphery of disk 8 is to alternately switch the actuating current from terminal 75 to terminal 78 of the thermostat and vice versa.

The elimination of manual control by the use ofthe automatic feature and application of the uniform and adjustable feed, combined with the type of grate which gives a fuel bed of uniform thickness, renders the rateof combustion very uniform, and en` ables the rate of fuel delivery to be adjusted to that best adapted to yproper combustion. The apparatus therefore causes a considerable portion of the gas to be consumed which would be driven off and wasted by an method which delivers the fuel in quantitles, either by hand or by machinery, and the result is a considerable economy and reduction in smoke. lit is understood that the apparatus herein shown is in the form in which l prefer to construct it. However,

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different furnaces may require considerable variation in the type of fuel feed or ofthe the same function as the control apparatus y herein shown. l do not restrict the types of the various elements employed in my invention except as the same may be restricted by the claims hereinafter made,

What lf claim as my invention is 1. yfhe combination, with a furnace, of a mechanical fuel feed, means of connecting said fuel feed to the furnace, a control apparatus adapted to open and close the drafts of the furnace and start and stop the fuel feed, a time Vdevice ada ted to oerate said furnace and fuel feed for a efinite time pe- ,riodi'cally irres ective of temperature requirements, an a thermostat adapted to control the o eration of said furnace and fuel feed'at a l other times according toth temperature requirements.

2. The combination, with a furnace, of a conical grate therein, a mechanical fuel feed, means of connecting said felfeed to the furnace, an electrically operated control afpparatus adapted to open and close the dra of the furnace and start and stop the fuel feed, a time device so constructed as to con-v trol the operation of the control apparatus and cause the furnace to operate for a definite time periodically irrespective of teml to the furnace; an electrical device adapted to open and close the drafts of the furnace and start and stop the mechanical fuel feed; a time device adapted to so operate said electrical device that the furnace and fuel feed are'operated for a definite time periodically irrespective of the temperature requirements, and which time device is also adapted to so change the thermostat connections that said electrical device is controlled by the thermostat according'to the temperature requirements at all times lother than said de nite periodical times.

4. In combination: a thermostat located at some point at which it is desired to regulate the temperature of the air; a furnace for the purpose of supplying heat to the point at which the thermostat is located; a conical grate in the furnace; a mechanical device for feeding fuel to the furnace; means of connecting said fuel feed to the furnace; an electrical device adapted to open and close the drafts of the furnace and start and stop the'fuel feed; a time device adapted to so operate said electrical device that the furnace and fuel feed are operated for a definite time periodically irrespective of the temperature requirements, and which timel device is also adapted to so change the thermostat connections that said electrical device is controlled by the thermostat according to the temperature requirements at all times other than said deinite periodical times.

In Witness whereof I have set my hand int 

